Roller/foot device castor

ABSTRACT

A roller/foot device ( 1 ) comprising a cylindrical outer sleeve ( 10 ), a guide sleeve ( 20 ) arranged inside the outer sleeve ( 10 ), locking sleeve ( 30 ) arranged inside the outer sleeve ( 10 ), a spring device where one end abuts against the outer sleeve&#39;s closed end ( 13 ) and the other end abuts against one end portion of the guide sleeve or the locking sleeve and a roller element ( 41 ) which is rotatably mounted abutting against the locking sleeve&#39;s ( 20 ) end portion which is located at the extreme end of the outer sleeve ( 10 ). The sleeves comprise ribs which can slide towards each other and cause the roller element ( 41 ) to assume different positions in the longitudinal direction of the outer sleeve ( 10 ) when the device ( 1 ) is subjected to forces. The device ( 1 ) can thereby be employed as a roller device with the roller element ( 41 ) in an outer position and as a foot device with the roller element ( 41 ) in an inner position.

The present invention relates to a device for moving an object by meansof a roller device which can be concealed in a sleeve body.

Roller devices are often employed when moving objects in order to reducethe load and facilitate manoeuvring. The roller devices may be directlyattached to the object that has to be moved, either releasably or as anintegrated part of the object. The object may also be placed on asupport unit equipped with roller devices. Objects and support unitsequipped with roller devices and used for moving objects are often alsorequired to be capable of assuming a stationary position.

One solution for achieving such a position will be to equip the rollerdevices with brake means. Particularly when using roller devices onobjects where a high degree of stability is required, and especiallywhere the objects in themselves are heavy or are carriers of heavyand/or unstable loads, it will often not be sufficient to equip theroller device with ordinary brake means. This applies particularly inconnection with furniture elements and objects which have to remainstationary for a lengthy period.

It is therefore an object of the present invention to provide technicalsolutions whereby an object can both be moved and will be capable ofachieving a position where the object remains stationary relative to thebase.

An arrangement of this kind for permitting an object to both be movedand remain stationary is known from DE 198 01 509. In this publication adevice is described for achieving easy displacement of a piece offurniture, using a roller body and a spring mounted in a sleeve whichforms part of the leg of a piece of furniture. When the furniture isunloaded, the spring will push the roller body out of the chair leg intoa position where the furniture can be moved. When the furniture isloaded against the ground, the roller body is pressed into the leg ofthe furniture and in this condition the furniture will remain stationaryrelative to the base.

In the solution disclosed in DE 198 01 509 the device is not equippedwith means or arrangements for securing the roller body in the rollingposition. A drawback of the solution disclosed in DE 198 01 509 is thatif the furniture is loaded or the actual roller body meets an obstacleon the floor, the furniture's capacity to move will be diminished, sincethe roller body will be partly or entirely pushed into the sleeve.

EP 0153832 illustrates a furniture castor which can be moved between aretracted position and an extended position. The castor is attached to arod connected to two elements with cam-shaped surfaces which control theposition of the rod.

Both of the above-mentioned solutions are bulky and unsuitable for beingfitted to many types of furniture, since they require too much space aswell as spoiling the aesthetic appearance of the object to which theyare attached.

The object of the present invention is to provide a solution whichimproves the disadvantages of the technical solution known from DE 19801 509. In particular, it is an object of the present invention toachieve a solution which is small and compact and which ensures thatduring displacement the roller device is kept in a rolling position andis not unexpectedly pushed into the sleeve.

The above objects of the invention are achieved by means of the featuresin the patent claims.

The solutions proposed in the present invention may be employed togetherwith objects within a number of areas of application. These may includefurniture elements, television sets, trolleys for use in warehouses,laboratories, factories or workshops, etc. The invention will be ideallysuited for transport of objects which particularly require a smooth andprecise pattern of movement, etc.

The invention may be employed in connection with moving objects not onlyalong a base which is horizontally oriented, but also along inclined andvertical bases.

In an embodiment the invention may be envisaged provided in such amanner that the sleeves can be removably mounted directly on to theobject that requires to be moved. In such an embodiment a support unitin the form of a trolley or the like for moving objects will be renderedsuperfluous.

The invention is small and compact and will therefore be suitable formounting on many types of objects and will have little or no effect onthe object's appearance.

In an embodiment the sleeve may be equipped with ball bearings, thusproviding a rotatable attachment to the movable object. In an embodimentan outer sleeve may be employed for mounting the sleeve in which theroller device is to be received. The roller device to be employedaccording to the invention may be in the form of a wheel, a ball oranother body which is capable of generating movement directly in contactwith a base.

In principle the roller/foot device according to the invention comprisesan outer sleeve, a spring device, a guide sleeve and a locking sleeveadapted to be able to be inserted into the outer sleeve and a rollerelement.

In an embodiment the roller/foot device also comprises several ballbearings and a locking ring.

In a further embodiment the roller device also comprises a bearing ringmounted in the locking sleeve inside the locking ring.

The outer sleeve is in the form of a hollow cylinder where one end iscompletely or partly closed by an end surface and one end is open. Theinner wall of the outer sleeve comprises first elongated ribs extendingin the outer sleeve's longitudinal direction. The ribs are arranged inparallel round the sleeve's circumference with grooves between. One endsurface of the ribs is inclined and comprises a step (catch). In anembodiment, on the outside of the outer sleeve are mounted tensionelements which may, e.g., be cut out of the actual outer sleeve andwhich protrude slightly from the outer surface of the outer sleeve.These tension elements are flexible and can be pressed into alignmentwith the outer sleeve's outer surface, in which case they will exert anoutwardly directed counterforce.

The guide sleeve and the locking sleeve are cylindrical with an externaldiameter which is slightly smaller than the inner diameter of the outersleeve, with the result that they fit closely into the outer sleeve. Theguide sleeve's outer wall comprises second ribs adapted to fit into thegrooves between the first elongated ribs on the outer sleeve when theguide sleeve is inserted into the outer sleeve. The end surfaces of thesecond ribs are also inclined, and the end portions advantageouslycomprise two inclined surfaces with opposite inclination, with theresult that the end portion is v-shaped. The guide sleeve's end portioncan act as an abutment for a spring device when the guide sleeve isinserted into the outer sleeve, for example by one end of the guidesleeve comprising an end surface. The spring device also abuts againstthe inside of the outer sleeve's end surface and may be attachedthereto, with the result that it is located between the outer sleeve andthe guide sleeve. The purpose of the outer sleeve's end surface is toprovide abutment for the spring device and it may be designed in asuitable manner, such as, for example, a whole surface, a surface withone or more holes, ribs, etc. Alternatively, the spring device may abutagainst the locking sleeve's end portion.

The locking sleeve's outer wall comprises third ribs with the samewidth, arranged at the same distance apart as the second ribs, where theend surface of the third ribs is inclined at an angle which is adaptedto the first ribs' inclined end portions and abuts against the secondribs' end portions.

The roller element is attached abutting against the locking sleeve's endportion which faces outwards towards the outer sleeve's open end, thusenabling the roller element to rotate. In a preferred embodiment theroller element is a ball, but it may also comprise a wheel mountedrotatably against the locking sleeve, or another suitable rotatableelement. The ball is made of a hard material, such as for example steel,plastic or the like, to enable it to run easily over the base. In apreferred embodiment the ball is made of a softer core with a hard outershell.

In a further embodiment the locking sleeve also comprises a cup-shapedrecess in the end facing out towards the outer sleeve's open end, therecess being adapted to receive several ball bearings and the rollerelement. The ball bearings are provided in the recess between thelocking sleeve and the roller element, thus enabling the roller elementto roll on the ball bearings with minimal friction. The roller elementand the ball bearings are kept in the recess by means of a locking ring.The locking ring is adapted to be able to be clamped into the lockingsleeve and has an aperture of such a size that the roller elementprotrudes slightly from the ring and can roll against a surface. In anembodiment the locking ring has inclined abutment surfaces, thusproviding the roller element with a smooth rotational motion.

Placing the roller element in the recess also contributes towards makingthe device according to the invention small and compact.

The bearing ring featured in the further embodiment of the invention isa ring which is adapted to be located between the locking ring and theball bearings. The bearing ring comprises at least one spring mechanismsuch as, e.g., flexible teeth to prevent the ball bearings from comingtoo far down along the sides of the roller element with the result thatthere are very few ball bearings at the top of the roller element andthereby considerable point loading on both the roller element and thelocking sleeve's recess. The spring mechanism improves the circulationof ball bearings round the roller element, thereby extending the life ofthe ball bearings and giving less rolling friction.

The roller/foot device may, for example, be used as a furniture castorby fitting it to the piece of furniture that has to be capable of beingrolled. The attachment can be easily implemented by pressing the outersleeve into a suitable aperture in the piece of furniture, for example atable leg, sofa leg or the like. The tension elements on the outside ofthe outer sleeve will then be pressed together, holding the rollerdevice in position inside the aperture.

The weight of the furniture will then cause the roller element to bepressed inwards in the outer sleeve with a certain amount of force. Thespring force from the spring device will exert a counterforce withopposite direction. When the force acting inwards in the outer sleeve isgreater than the spring force, this will result in a movement of theguide sleeve and the locking sleeve inside the outer sleeve. The guidesleeve's ribs will slide in the grooves in the longitudinal directionbetween the outer sleeve's ribs and the end surfaces of the third ribson the locking sleeve will slide towards the end surfaces of the firstribs in the outer sleeve, thus giving the locking sleeve a movement inthe circumferential direction. This movement is stopped in one of twopositions: 1) when the locking sleeve's ribs abut against the steps onthe outer wall's ribs or 2) against the lateral edge of the outer wall'sribs. In the first case the inward movement of the guide sleeve and thelocking sleeve in the outer sleeve is stopped before the roller elementhas been pushed all the way into the outer sleeve and in this positionthe roller element can roll freely. In this case the roller/foot elementacts as a roller element. In the second case the inward movement of theguide sleeve and the locking sleeve in the outer sleeve is stopped afterthe roller element has been pushed all the way into the outer sleeve,with the result that the roller element is no longer able to roll overthe base. In this case the roller/foot element acts as a foot element.If the base is hard, the roller element will be in abutment against thebase, but the flexibility of the spring device causes the weight to reston the outer sleeve. It is an advantage that the distance between thespring device's two abutments of the spring device is sufficiently largeto ensure that the spring device is not completely compressed in theroller element's inner position in order to avoid instability.

To enable the guide and locking sleeves to continue their movements inthe outer sleeve, the force acting inwards in the outer sleeve must beless than the force from the spring device, for example by lifting thefurniture slightly. The roller element, the guide and locking sleevesare then pressed into their outermost position in the outer sleeve. Whenthe furniture is then lowered back on to the floor, the sleeves willonce more be moved as described above until they stop in the secondposition.

The device according to the invention may of course be used inconnection with any object that requires to be moved. The device may beaffixed to the object in many ways, such as for example by screwedconnection, gluing, Velcro fastening, etc. in addition to the method ofattachment described above.

When using surfaces which are easily marked or scratched, the outer edgeof the outer sleeve may be protected by a pad of a suitable materialsuch as foam, plastic, felt or the like. The pad will preferably bedoughnut-shaped with an outer diameter equal to or larger than the outersleeve's outer diameter and an inner diameter larger than or equal tothe diameter of the protruding part of the roller element, in order toavoid obstructing the roller element's rolling motion.

The invention and its mode of operation will be described in greaterdetail below with reference to the drawings.

FIGS. 1-4 illustrate an embodiment of the present invention with rollerball, guide and outer sleeves in four respective positions.

FIG. 5 illustrates a second embodiment of the invention where the rollerelement is mounted in the locking sleeve by means of universal mounting.

FIG. 6 illustrates a detail of a further embodiment of the inventionwhere a bearing ring supports the ball bearings in FIG. 5.

FIG. 7 illustrates one embodiment of the bearing ring in FIG. 6.

FIG. 8 illustrates a second embodiment of the bearing ring in FIG. 6.

FIG. 1 illustrates the device 1 according to the invention with noforces acting inwards in the outer sleeve 10. In this embodiment theroller element is a ball 41. In FIG. 1 the ball is kept in its outermostposition in the outer sleeve 10 by the force from the spring device (notshown). The spring device presses the guide sleeve 20 outwards towardsthe outer sleeve's 10 open end 17. The ribs 21 on the guide sleeve slidein the grooves between the outer sleeve's ribs 11. The end surfaces(22,23) of the ribs 21 on the guide sleeve abut against the end surface32 of the ribs 31 on the locking sleeve 30, and the locking sleeve 30and thereby the ball 41 are thereby also pressed outwards towards theouter sleeve's 10 open end 17. In this embodiment the outer sleeve 10has outwardly protruding edge pieces 18 which prevent the locking sleeve30 and the guide sleeve 20 from being pushed out of the outer sleeve 10.

The ball 41 is attached against the locking sleeve 30 by means of alocking ring 40 which is clamped into the opening of the locking sleeve,with the result that a movement of the locking sleeve 30 along the outersleeve's longitudinal direction leads to a corresponding movement of theball 41.

In FIG. 1 tension elements 14 are also illustrated mounted round theoutside of the outer sleeve 10. In this embodiment the tension elements14 are produced by cutting out slots in the outer sleeve 10, but theymay also be glued or attached to the outer sleeve in another suitablemanner. The tension elements 14 have an outwardly protruding upperportion 19. When the device 1 is inserted in a hole for attachment to anobject, the tension elements 14 are placed under tension against thewalls of the hole, thus keeping the device 1 in position.

FIG. 2 illustrates the device 1 after an inward force in the outersleeve has been applied to the ball 41 with initial position asillustrated in FIG. 1, for example by the weight of a piece of furniturepressing the device down against a floor. The locking sleeve 30 and theguide sleeve 20 are forced inwards until the end surfaces 32 of thelocking sleeve's ribs 31 come into abutment against the end surfaces 15of the outer sleeve's ribs 11 and slide against them until they stopagainst the steps 16 on the ribs in the outer sleeve. This slidingmovement has given the locking sleeve 30 a rotating motion in thecircumferential direction. Further inward movement of the ball 41, thelocking sleeve 30 and the guide sleeve 20 in the outer sleeve 10 isprevented by the step 16 and in this position a part of the ball 41protrudes outside the opening of the outer sleeve. In this position theball 41 can rotate freely and the device 1 can be used as a castor formoving the object (for example a piece of furniture) to which it isattached. The grooves 24 between the ribs 21 on the guide sleeve 20 haveend surfaces comprising two inclined surfaces 26, 27 with oppositeinclination, thus making the end portion v-shaped. In this case thebottom of the “v” is located on the right of the step 16 in the inclinedend surface 15 of the outer sleeve's ribs 11, with the result that theleft-hand upper edge of the locking sleeve's ribs 31 abuts against theright-hand inclined end surface 26 of the guide sleeve's ribs.

In FIG. 3 the device 1 as illustrated in FIG. 2 has been released fromthe external forces, for example by the object to which it is attachedbeing slightly raised from the base.

The force from the spring device then presses the guide sleeve 20towards the open end 17 of the outer sleeve 10. The locking sleeve'sribs 31, which are located in abutment against the left-hand inclinedend surface 26 of the guide sleeve's groove, is also forced outwardstowards the outer sleeve's open end and slides on the inclined endsurface 26, thus giving the locking sleeve a movement in thecircumferential direction past the step 16 on the outer sleeve's ribs11. In this position the ball 41 is located in a position correspondingto the position in FIG. 1, furthest out of the outer sleeve 10.

When the device 1 is once again exposed to external forces, i.e. withthe ball 41 now in its initial position as in FIG. 3, for example by theweight of the object with castors again resting on the device 1, weobtain the situation illustrated in FIG. 4. The ball 41 and the lockingsleeve 30 are forced inwards in the outer sleeve 10 until the endsurface 32 of the locking sleeve's ribs 31 comes into abutment againstthe step 16 in the end surfaces 15 of the outer sleeve's ribs 11 andslides towards them until they pass the step 16, enters the groovesbetween the outer sleeve's ribs 11 and stops. This sliding movement hasgiven the locking sleeve 30 a rotating motion in the circumferentialdirection. Further inward movement of the ball 41, the locking sleeve 30and the guide sleeve 20 in the outer sleeve 10 is prevented by the outeredge 34 of the locking sleeve 30 abutting against the outer sleeve'sribs 11. In this position the whole ball 41 is in a retracted positionaligned with or inside the outer sleeve's aperture 17. In this positionthe ball 41 is unable to roll over the base and the device 1 acts as afoot element.

By means of repeated application and release of forces on the device 1,the ball 41 will repeatedly assume the positions described above insequence, thus permitting the device 1 to be easily moved from a rollingposition to a foot position and vice versa.

In FIGS. 1-4 the ribs 21 on the guide sleeve 20 have two inclinedsurfaces with opposite inclination, thus making the end portionv-shaped. However, this end portion may also have other shapes, forexample a rounded shape, asymmetrical v-shape, a inclined surface and astraight surface or the like, as long as it has the desired effect, viz.to guide the ribs 31 on the locking sleeve past the edge 25 or the step16 of the ribs 11 on the outer sleeve 10 so that the end surface of theribs 31 on the locking sleeve 30 comes into abutment against the endsurfaces of the step 16 and the ribs 11 respectively.

In FIG. 5 a second embodiment of the invention is illustrated where theball 41 is mounted by means of universal mounting. In this case thelocking sleeve 30 comprises a cup-shaped recess 35 in the end facing outtowards the outer sleeve's open end. In the recess 35 are placed severalball bearings 50 and the ball 41 abuts against the ball bearings 50,thus enabling the ball 41 to roll with minimal friction. The ball 41 andthe ball bearings 50 are kept in the recess 35 by means of a lockingring 40. The locking ring 40 is adapted to be able to be clamped intothe locking sleeve 30 and has an aperture of such a size that the ball41 projects slightly from the ring 40 and can roll against a surface.

FIG. 5 also illustrates the spring device 5 abutting against the insideof the outer sleeve's end surface 13 and the guide sleeve's 20 endsurface 28.

FIG. 6 is a sectional view of a detail of a further embodiment of theinvention. The bearing ring 51 is a ring which is adapted to be locatedbetween the locking ring 40 and the ball bearings 50. The bearing ring51 comprises a spring mechanism 52 such as, e.g. flexible teeth toprevent the ball bearings from coming too far down along the sides ofthe ball 41, with the result that there are very few ball bearings atthe top of the ball 41 and thereby considerable point loading on boththe ball 41 and the locking sleeve's 30 recess. The spring mechanism 52also improves the circulation of ball bearings 50 round the ball 41,thereby extending the life of the ball bearings 40 and giving lessrolling friction.

FIG. 7 illustrates a possible embodiment of bearing ring 53 with springmechanism 54.

FIG. 8 illustrates an alternative embodiment of bearing ring 55 withspring mechanism 56.

1. A roller/foot device (1), characterised in that it comprises acylindrical outer sleeve (10) with one end completely or partly closed(13) by an end surface and one open (17) end, where the outer sleeve'sinner wall(s) comprise first elongated ribs (11), which extend in theouter sleeve's longitudinal direction with inclined end portions (15)with a step (16) and which are arranged in parallel with grooves betweenround the circumference of the sleeve (10), a guide sleeve (20) arrangedinside the outer sleeve (10) where the guide sleeve's outer wallcomprises second ribs (21) where the width of the second ribs is equalto or less than the grooves between the first ribs (11) and which haveend portions comprising at least one inclined surface (22,23) andgrooves (24) between the ribs (21) which similarly have end portionswith at least one inclined surface (26,27), a locking sleeve (30)arranged inside the outer sleeve (10) where the outside of the lockingsleeve comprises third ribs (31) with the same width and arranged at thesame distance apart as the second ribs (21) in the guide sleeve (20),and which have inclined end portions (32) at an angle which is adaptedto the first ribs' inclined end portions (15) and which abut against thesecond ribs' end portions (22), a spring device where one end abutsagainst the outer sleeve's closed end (13) and the other end abutsagainst one end portion of the guide sleeve or the locking sleeve, aroller element (41) which is rotatably mounted abutting against thelocking sleeve's (20) end portion located at the extreme end of theouter sleeve (10), with the result that when the roller element (41) issubjected to a force that acts inwardly in the outer sleeve (10), thespring device will exert a counterforce which presses the roller element(41) towards the outer sleeve's open end, when the force that actsinwardly in the outer sleeve is sufficiently great (greater than theforce from the spring device), the second ribs (21) on the guide sleevewill slide in the longitudinal direction in the grooves on the outersleeve (10), the end portions (32) of the third ribs will slide towardsthe end portions (15) of the first ribs, thus generating a movement ofthe locking sleeve (30): in the circumferential direction, the movementin the circumferential direction being stopped by the third ribs (31)abutting against the steps (16) on the first ribs' end surfaces (15) ina position where the roller element (41) is in its first position, oragainst the first ribs' (11) side walls in a second position where theroller element (41) is in its second position, depending on the rollerelement's initial position, when the force acting inwardly in the outersleeve (10) is less than the force from the spring device, the rollerelement is pressed into its outer, third position and when the rollerelement (41) is subjected to repeated forces in the inward direction,the roller element will assume a sequence of positions in the outersleeve's longitudinal direction, where the roller element in the firstposition protrudes from the outer sleeve and in the second position iscompletely inside the outer sleeve.
 2. A roller device according toclaim 1, characterised in that it further comprises several ballbearings and a locking ring and that the locking sleeve is provided witha cup-shaped recess in the end facing out towards the outer sleeve'sopen end, the recess being adapted to receive the ball bearings and theroller element, and the locking ring is designed to be able to beclamped into the locking sleeve so that the ball bearings and the rollerelement are held against the recess in the locking sleeve.
 3. A rollerdevice according to claim 1, characterised in that it further comprisesa bearing ring which is adapted to fit between the locking ring and theball bearings.
 4. A roller device according to claim 3, characterised inthat the bearing ring comprises at least one spring mechanism such as,e.g. flexible teeth.
 5. A roller device according to claim 1,characterised in that the end portions of the second ribs on the guidesleeve comprise two inclined surfaces.
 6. A roller device according toclaim 1, characterised in that the roller element is made of asoft/flexible material surrounded by a harder material.
 7. A rollerdevice according to claim 1, characterised in that the outer sleeve alsocomprises tension devices for attachment to a piece of furniture.
 8. Aroller device according to claim 1, characterised in that a protectivepad is provided on the outer sleeve's outer edge.
 9. A roller deviceaccording to claim 8, characterised in that the pad is doughnut-shapedwith an outer diameter equal to or larger than the outer sleeve's outerdiameter.